1. Field of the Invention
This invention relates to an apparatus for cleaning refractory lined conveyor troughs for molten metals and slags, and in particular, to the equipment used to move the apparatus along the conveyor trough during the cleaning of the trough wall.
2. BACKGROUND INFORMATION
German Patent No. 32 25 015 discloses an apparatus for the cleaning of refractory-lined conveyor troughs using conveyor chains circulating on a rotating drum. This apparatus can be moved along the trough by means of wheels which are guided in tracks on both sides of the trough. However, the arrangement disclosed therein, with two guide tracks in the form of broad grooves for the four wheels, is considered an undesirable solution for the following reasons. Under the thermal effect of molten metal and hot slags, the floor of the building, and in particular, the foundation in the vicinity of the trough, can be deformed, which leads to permanent deformation of the tracks permanently installed on or in the foundation, so that it is impossible to achieve a perfect guidance parallel to the trough and uniform contact of all the wheels. Irregularities in the guideway not only complicate the operation of the apparatus, but also have a disadvantageous effect on the cleaning process. Such tracks also present an increased risk of accidents during the operation of the trough. Such tracks may also become unusable if the trough overflows.
It is known, of course, that a three-point contact guarantees the stable position of an object even on an uneven floor. In the present case, however, the carriage of the apparatus, whose overall length is relatively short in relation to its width, must be guided in as parallel a fashion as possible to the center of the trough on a floor which is continuously changing under the influence of thermal factors. These changes result not only in height differences of the contact on the tracks, but also to changes in the track width, if two tracks are used. It should also be noted that the cleaning process can also exert lateral forces on the carriage. The present invention solves this problem in a simple manner, which manner is also suitable for an operating environment of a blast furnace. The guidance of the carriage according to the invention is particularly advantageous for use on non-track guided equipment, e.g. excavator vehicles, on which a cleaning head is mounted.